前置詞(preposition)Besideの意味は、
“by or at the side of; next to;near
compared with
apart from”
訳すと、
「のそばに(の横に) 比べると をはずれて」
The cat sat beside the dog.
Beside the small cat, the dog seemed extra large.
What you just said is beside the point.
前置詞Besidesの意味は、
“apart from in addition to other than; except”
訳すと、
「のほかに(も)、 を除いて」
Besides the governor, there were many other politicians attending the event.
Everyone besides Charles was able to finish the assignment.
What can Sam do besides sales?
英語の文法練習はこのテキスト・Understanding and Using English Grammar with Audio CDs and Answer Key (4th Edition)をお勧めです。文法の参考書は、こちらのガイド・Practical English Usageも実用的です。私も両方レッスンで使っています。